Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MULTILAYER TEXTILE ASSEMBLY FOR USE IN FOOTWEAR
TECHNICAL FIELD
The technical field generally relates to the field of textile or fabric
technology. More
particularly, the invention relates to a multilayer textile assembly for use
in
footwear.
BACKGROUND
The present application generally relates to a fabric material for use as a
thermal,
liquid resistant and water vapor permeable barrier in footwear. More
specifically,
the present application relates to protective boots for firefighters and
military
soldiers. Generally, a work boot includes a boot liner, which provides thermal
insulation. Traditional textiles used as thermal insulating barriers in boot
liners
contain a thick non-woven material, such as felts and neoprene. However, this
particular type of material functions by trapping air in the textile.
Problematics associated with conventional boot liners include the non-
resilient
behavior in compression of the fabric or poor resistance to compression. When
high compressive strength is applied to a standard boot liner fabric, thermal
insulation is reduced due to a loss in air-filled spaces and the thinning down
of the
fabric when compressed (the non-resilient behavior in compression). It is
essential
for a boot liner to be compression-resistant as it also significantly affects
the
comfort of the foot. Conventional work boots also do not provide proper water
elimination and water barrier which may also seriously affect foot comfort.
Consequently, some unsolved problems related to the working footwear industry
includes the prevention of moisture accumulation, poor moisture-wicking
performances, slow drying, the weight, limited comfort, poor thermal
properties,
poor insulation properties, durability and high cost.
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There is therefore a need for an alternative technological approach for
protective
boots one or more of the above-mentioned issues typically associated with
conventional liners.
SUMMARY
According to one aspect, the present application relates to a multilayer
textile
assembly for use in a footwear, the multilayer textile assembly comprising,
successively:
- a first layer comprising a woven or knitted fabric of nylon or polyester
or a
blend thereof with natural or synthetic fibers;
- a second layer comprising a membrane made with a waterproof-breathable
material; and
- a third layer, comprising:
o an outer fabric sheet and an inner fabric sheet extending in a
superposed relationship, each of said inner and outer fabric sheets
independently comprising a woven or knitted fabric of nylon or
polyester or a blend thereof with natural or synthetic fibers; and
o at least one monofilament yarn connecting the outer and inner fabric
sheets and arranged in a pile structure forming an air-filled spacer
between said outer and inner fabric sheets.
In one aspect, the layers of the multilayer textile assembly all exclude fire
resistant
fibers.
In one embodiment, the fabric of the first layer is preferably made with nylon
or
polyester or a blend thereof with natural or synthetic fibers. In one example,
the
first layer is typically manufactured by weaving, warp knitting or circular
knitting.
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In one embodiment, the membrane of the second layer may include a microporous
waterproof-breathable material, and may include an expanded
polytetrafluoroethylene (ePTFE). The membrane may further be treated or coated
on at least one of its sides with a hydrophilic polymer. In one example, the
.. hydrophilic polymer includes polyurethane (PU); for example, copolymers of
urethane such as polyether-urethane or polyester-urethane. In another example,
the treatment or coating of the hydrophilic polymer onto the membrane may be
made by roll coating, film lamination, spraying or dots.
In a further embodiment, the inner and outer fabric sheets of the third layer
are
preferably made with nylon or polyester or a blend thereof with natural or
synthetic
fibers. In one example, the fabric sheets are manufactured by weaving, warp
knitting or circular knitting.
In a yet further embodiment, the at least one monofilament yarn of the third
layer
is made with a material similar to the one used in fishing wires. In one
example,
the monofilament yarn is made with nylon or polyester.
In a further embodiment, the three successive layers of the multilayer textile
assembly are linked together. In one implementation, the second layer may be
laminated to the first layer and the hydrophilic polymer of the second layer
may
bind the second layer to the third layer.
According to another aspect, the present application relates to the use of the
multilayer textile assembly in footwear including boots, such as work boots,
military
boots or combat boots. In one variant of interest, the footwear may be a
firefighter
boot.
In one embodiment, the footwear is a firefighter boot. In one example, the
firefighter
boot includes a rigid protective shell and a boot liner made with the
multilayer textile
assembly that fits inside the protective shell. In one example, the multilayer
textile
assembly is arranged so that its third layer extends on the side of the foot,
whereas
the first layer extends on a side of the protective shell.
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According to another aspect, the present application relates to a footwear
comprising a multilayer textile assembly as defined herein.
According to another aspect, the present application relates to a boot liner
comprising a multilayer textile assembly as defined herein.
According to a further aspect, the present application relates to a method for
producing a multilayer textile assembly for use in a footwear, the method
comprising the steps of:
- providing a first layer comprising a woven or knitted fabric of nylon or
polyester or a blend thereof with natural or synthetic fibers;
lo -
laminating a second layer to the first layer, the second layer comprising a
membrane made with a waterproof-breathable material which is optionally
microporous, and may for example comprise an expanded
polytetrafluoroethylene (ePTFE); and
- providing a third layer including:
a providing an outer fabric sheet and an inner fabric sheet extending in
a superposed relationship, each of said inner and outer fabric sheets
independently comprising a woven or knitted fabric of nylon or
polyester or a blend thereof with natural or synthetic fibers; and
connecting the outer and inner fabric sheets with at least one
monofilament yarn arranged in a pile structure forming an air-filled
spacer between said outer and inner fabric sheets; and
- binding the third layer to the second layer.
Other features and advantages of the multilayer textile assembly when used in
footwear will be better understood upon reading the embodiments thereof and
the
related appended drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side view of a multilayer textile assembly according to
one
embodiment.
FIG. 2 is a schematic side view illustrating the third layer of the multilayer
textile
5 assembly of FIG. 1.
FIG. 3 is a representation of footwear provided with a liner made with a
multilayer
textile assembly according to one embodiment.
DETAILED DESCRIPTION
The following detailed description and examples are illustrative and should
not be
interpreted as further limiting the scope of protection.
All technical and scientific terms and expressions used herein have the same
definitions as those commonly understood by the person skilled in the art when
relating to the present technology. The definition of some terms and
expressions
provided below take precedence over the common meaning given in the
litterature.
When an interval of values is mentioned in the present application, the lower
and
upper limits of the interval are, unless otherwise indicated, always included
in the
definition.
The term "approximately" or the equivalent term "about" as used herein means
approximately in the region of, and around. When the term "approximately" or
"about" is used in relation to a numerical value, it modifies it, for example,
above
and below by a variation of 10% in relation to the nominal value. This term
may
also take into account, for example, the experimental error of a measuring
apparatus or rounding.
In accordance with one aspect, there is provided a multilayer textile assembly
10.
For instance, the multilayer textile assembly 10 may be used in footwear.
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In the context of the present description, the term "footwear" may be
generally
understood to refer to an apparel or an article of clothing worn on the feet.
Non-
limiting examples of footwear include boots, such as work boots, military
boots or
combat boots. Alternatively, the footwear may also be snow boots, sport boots,
equestrian boots, hiking boots, ski boots, snowboard boots, pac boots, shoes,
athletic shoes, snowshoes, work shoes, boot socks, socks, sandals or insoles.
In
one variant of interest, the footwear may be a work boot. For instance, the
work
booth may be a firefighter boot, as presented in more detail below.
The term "textile" as used herein is meant to generally refer to an element
manufactured from natural or synthetic (i.e., man-made) fibers or filaments or
monofilaments. Non-limiting examples of synthetic fibers or filaments include
polyester, polyamide (e.g., Nylon) aramid or meta-aramid (e.g., KevlarTm,
technora TM, Twaron TM, NomexTM, TeijinvonexTm, KermelTM and HecracronTm),
ZylonTm, polyethylene (PE), polytetrafluoroethylene (ePTFE), polyphenylene
sulfide (PPS), polyetheretherketone (PEEK), acrylic, modacrylic, polyurethane
(e.g., spandex or Lycra TM), oleofin fibers, polylactide fibers (ingeo),
metallic fibers
(e.g., lurex) and milk or casein protein fibers. Non-limiting examples of
natural
fibers or filaments include wool, silk, cashmere, hemp, flax (linen), cotton
and
bamboo fibers. Non-limiting examples of such elements include yarns, threads
and
fabrics.
Also, the expression "seam sealing" may be understood to refer to the
application
of seam tape or seam-sealing glue to cover the holes made by the needle in the
sewing process in order to substantially maintain the waterproof properties of
the
textile.
Referring to FIG. 1, a multilayer textile assembly 10 according to one
embodiment
is schematically illustrated. The multilayer textile assembly 10 includes
successively at least three layers. The multilayer textile assembly 10
includes a
first layer 12 which is made with a fabric including a material made with
fibers,
filaments or yarns; provided, however, that the materials exclude fire
resistant
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fibers, filaments or yarns. The fabric of the first layer 12 is typically
manufactured
by weaving, warp knitting or circular knitting. Alternatively, the fabric of
the first
layer 12 may also be made with a non-woven material. For example, the fabric
material of the first layer 12 may be made with synthetic polyamide fibers
such as
nylon or synthetic polymer composed of a complex ester such as polyester or a
blend thereof with natural or synthetic fibers to obtain blended properties.
Natural
fibers may include, for example, wool or cotton. For example, the synthetic
fibers
may include viscose, acetate, acrylic, polyester, polyethylene, polypropylene
and
polyamide (e.g., nylon). In one variant of interest, the fabric of the first
layer 12 may
be made with a nylon or a polyester. As mentioned above, the fabric may be
made
with a blend of nylon or polyester with synthetic or natural fibers; for
example,
nylon, cotton, polyester, wool, polypropylene and viscose to obtain
substantially
improved attributes of the materials contained in such a blend. In some
implementations, the total weight of the first layer 12 may be within the
range of
from about 1 to about 2 ounces per square yard (i.e. within the range of from
about
33.9 g.m-2 to about 67.8 g.m-2), limits included.
Still referring to the illustrated embodiment of FIG. 1, the multilayer
textile assembly
10 further includes a second layer 14. The second layer 14 may be protected by
the first layer 12 of the multilayer textile assembly 10. In some
implementations,
the second layer 14 may include a membrane made with a waterproof-breathable
material. The waterproof-breathable material may be microporous, and for
example may be made with expanded polytetrafluoroethylene (ePTFE).
Alternatively, the second layer 14 may include a membrane made with a non-
microporous hydrophilic material (not air permeable or non-breathable). The
non-
microporous hydrophilic material may, for example, be made with a polymer such
as polyester, polyether, polyurethane and their copolymers. Alternatively, the
second layer 14 may include a membrane made with a microporous waterproof-
breathable polyethylene.
In one implementation, the membrane of the second layer 14 may further be
treated or coated on at least one of its sides with a hydrophilic polymer. The
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hydrophilic polymer may include polyurethane (PU); for example, copolymers of
urethane such as a polyether-urethane or a polyester-urethane. The treatment
or
coating of a hydrophilic polymer onto the membrane may allow for optimal water
vapor transfer and protects the membrane from clogging. For example, the
treatment or coating of the hydrophilic polymer onto the membrane may be
applied
by roll coating, film lamination, spraying or dots. The treatment or coating
may be
applied to the foot-side of the textile, on its opposite side, or both. In one
example,
the treatment or coating is preferably applied on the foot-side of the
textile.
In some implementations, the membrane is made with a microporous waterproof-
breathable material that may also be described as a hybrid film that is liquid
resistant and water vapor permeable. In other words, the membrane is made with
a microporous waterproof-breathable material that provides liquid protection
and
the transfer of humidity and/or water vapor away from the foot of the wearer
of the
footwear, resulting in better comfort.
Still referring to the illustrated embodiment of FIG. 1, the multilayer
textile assembly
10 further includes a third layer 16.
Now referring to the illustrated embodiment of FIG. 2, which shows a schematic
side view illustrating the third layer 16. The third layer 16 may include an
outer
fabric sheet 18 and an inner fabric sheet 20 extending in a superposed
relationship.
Each of the inner and outer fabric sheets 18 and 20 may include materials made
with fibers, filaments or yarns. This is provided however that the materials
exclude
fire resistant fibers, filaments or yarns. The fabric sheets are typically
manufactured by weaving, warp knitting or circular knitting. The fabric sheets
are,
for example, made with synthetic polyamide fibers such as nylon or synthetic
polymers composed of a complex ester, such as polyester, or a blend thereof,
with
natural or synthetic fibers to obtain blended properties. Natural fibers may
include,
for example, wool or cotton. For example, the synthetic fibers may include
viscose,
acetate, acrylic, polyester, polyethylene, polypropylene and polyamide (e.g.,
nylon). As mentioned above, the fabric sheets may be made with a blend of
nylon
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or polyester and with synthetic or natural fibers. The blend may include a
combination of nylon or polyester with other synthetic or natural fibers or
polymers
such as cotton, wool, polypropylene and viscose.
Still referring to the illustrated embodiment of FIG. 2, the third layer 16
may further
include at least one monofilament yarn 22 connecting the outer and inner
fabric
sheets 18 and 20. Although the description below mostly refers to the
monofilament yarn in the singular, it will be readily understood that in some
implementations more than one strand of monofilament yarn may be used to
connect the inner and outer fabric sheets without departing from the scope of
the
invention.
As its name would suggest, the monofilament yarn 22 is made with one filament
that runs the entire length of the yarn. The monofilament yarn 22 may, for
example,
be made with synthetic polyamide monofilaments such as nylon or monofilaments
of synthetic polymer composed of a complex ester such as polyester. For
example,
the monofilament yarn 22 may be made with a material that is similar to the
one
used in fishing wires. Alternatively, the monofilament yarn 22 may be made
with
nylon 610, nylon 612, or polyester, polyethylene and polypropylene.
In the illustrated embodiment of FIG. 2, the monofilament yarn 22 is arranged
in a
pile structure forming an air-filled spacer between the outer and inner fabric
sheets
18 and 20. The production of this pile structure includes superposing the
outer and
inner fabric sheets 18 and 20 and connecting them together at a multitude of
points
over their entire surfaces with the monofilament yarn 22 using a method
resembling that of manufacturing double piece velvet weaving. However, unlike
the manufacture of double piece velvet weaving, the outer and inner fabric
sheets
18 and 20 are not separated after their manufacture to produce two textiles
but
may rather be used uncut. The "piles" created in this manner may therefore
remain
connected to both fabric sheets.
In one implementation, the monofilament yarn 22 may be made with a material
selected for its low absorbency, improved compressive strength and improved
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resilience. The thickness of the third layer 16, including the air-filled
spacer, may
vary from about 1 to about 7 mm, or from 3 to 4 mm depending on the required
thermal insulation for the footwear. Indeed, the thickness of the third layer
16
affects thermal insulation as well as comfort and moisture dissipation
properties.
5 As mentioned above, the monofilament yarn 22 is arranged in a pile structure
forming an air-filled spacer between said outer and inner fabric sheets 18 and
20.
In one implementation, the air-filled spacer may provide a resilient behavior
in
compression (resistance to compression or compressive strength) of the
multilayer
textile assembly 10. Furthermore, the air-filled spacer directly influences
the
10 thermal insulation but also quick transfer of water vapor away from the
foot.
Advantageously, the use of the multilayer textile assembly 10 as described
herein
in a footwear may provide substantially superior thermal comfort and moisture
dissipation properties when compared with current commercial products made
with
non-woven material such as felts and neoprene. In one aspect, thermal comfort
properties may be attributed to the air-filled spacer which entraps air
resulting in
substantially improved thermal insulation. The resilient behavior of the air-
filled
spacer may substantially prevent the air-filled spacer to flatten under
compressive
strength and thus may substantially prevent the thermal insulation to be
decreased
due to the loss of air-filled spaces. The improved thermal insulation may
substantially improve the warmth and comfort of the foot. The moisture
dissipation
properties may be obtained through several processes. Furthermore, the water
resulting from the body heat or sweat is spread by capillarity through the air-
filled
spacer of the third layer 16 due to surface tension. In another aspect, the
membrane of the second layer 14 may include micropores that are large enough
to allow water vapor to escape but small enough to substantially prevent
liquid
water from the environment to penetrate the boot and ultimately reach its
wearer's
foot. Also, the treatment or coating of hydrophilic polymer onto the membrane
may
also allow an optimal water vapor transfer. Furthermore, the treatment or
coating
of hydrophilic polymer onto the membrane also protects the membrane from
clogging and thus allows for the membrane to retain its waterproof properties.
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Furthermore, the resilient behavior in compression which may be provided by
the
third layer 16, may also substantially improve the comfort; for example, by
substantially minimizing foot fatigue and stress. Such advantages may be of
particular interest in specialized footwear, such as work boots such as
firefighter
boots.
When referring back to FIG. 1, the three successive layers of the multilayer
textile
assembly 10 may be linked together. In one implementation, the second layer 14
may be laminated to a foot-side surface of the first layer (12). The
expression
laminated may be understood to refer to the preparation of a membrane that may
then be superposed to a textile which may then be firmly attached together by
bonding or impregnating and compressing under heat. Advantageously, the
hydrophilic polymer of the second layer 14 may bind the second layer to the
third
layer 16. The multilayer textile assembly 10 may therefore form a monolithic
structure without the need for stiches.
Referring to FIG. 3, there is shown an example of a footwear 24 provided with
a
multilayer textile assembly 10 according to one implementation. In the
illustrated
example, the footwear is a firefighter boot. Illustratively, the firefighter
boot includes
a rigid protective shell 26 which may for example be made with or include
rubber
or leather and may give shape to the firefighter boot. In the illustrated
example, the
firefighter boot further includes a boot liner 28 that fit inside the
protective shell.
The boot liners may be removable from the footwear or permanently attached,
sewn or sealed to it.
The boot liner 28 is preferably made with a multilayer textile assembly 10
according
to one embodiment described above, in whole or in part. The multilayer textile
assembly 10 is arranged such that its third layer 16 extends on the foot side,
whereas the first layer 12 extends on the side of the protective shell. In one
implementation, the boot liner 28 may be assembled by sewing the boot liner's
parts together. The stitch lines of the boot liner 28 may be made
substantially leak
proof, for example, by seam sealing.
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Another advantage of the third layer 16 is its substantially lower drying time
when
used either as a fixed, non-removable liner or as a removable liner,
especially
when compared to boot liners made with nonwoven fabrics, felts and neoprene.
The tickness of the multilayer textile assembly 10 may vary depending on the
different regions of the boot liner. In one embodiment, a thinner and lighter
air-filled
spacer may be provided for the upper part of the footwear, and a thicker and
heavier air-filled spacer may be provided under the foot or sole to
substantially
improve the comfort and substantially minimize fatigue and stress of the foot.
The
footwear as described herein thereby providing many benefits. For example,
.. thermal comfort is a feature of embodiments of the multilayer textile
assembly 10
as described herein. Other benefits may include comfort properties such as the
sensation of dryness and heat and moisture transference (water vapor
transfer),
low cost, durability, resilience, weight and comfort. The multilayer textile
assembly
10 may significantly improve the comfort of workers when compared to boot
liners
made with non-wovens, felts and neoprene. Other advantages may include the
flexibility of the multilayer textile assembly 10 especially for the upper
part of the
boot. This improved flexibility may provide improved mobility and ease of
movements such as knee flexing and ankle rotation. The improved mobility may
result in lower time for donning and doffing, and therefore may reduce the
energy
required for such operations.
Once again, numerous modifications could be made to the embodiments above
without departing from the scope of the invention.
